Process for the manufacture of hexafluoro-2-butene

ABSTRACT

Hexafluoro-2-butene (HFO-1336) is a low global warming potential blowing agent, refrigerant and solvent. This invention provides methods for making the compound, including the cis-isomer, from the readily available raw materials, carbon tetrachloride and ethylene. The trans-isomer formed in the process can be isomerized into cis-isomer by the use of an isomerization catalyst.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims domestic priority from commonly owned,copending, U.S. Provisional Patent Application Ser. No. 61/317,868,filed 26 Mar. 2010, the disclosure of which is hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

Hexafluoro-2-butene (HFO-1336) is a low global warming potential blowingagent, refrigerant and solvent. This invention provides a method formaking the compound, including the cis-isomer, which has the followingstructure:

SUMMARY OF THE INVENTION

The present invention provides a new and economical process to producehexafluoro-2-butene (HFO-1336) from readily available raw materials,carbon tetrachloride (CCl₄) and ethylene. Without wishing to be bound bytheory, it is believed that the hexafluoro-2-butene is produced throughseveral possible intermediates including, CCl₃CH₂CH₂Cl, Cl₃CH═CH₂,CCl₃CHClCH₂CCl₃, and CF₃CHClCH₂CF₃. The trans-isomer produced from thistechnology can be isomerized into cis-isomer over a judiciously selectedisomerization catalyst.

One embodiment of the present invention is a process for the manufactureof hexafluoro-2-butene comprising the steps of:

(a) contacting carbon tetrachloride with ethylene in the presence of aneffective amount of a metal catalyst complex comprising a metal and anorganic ligand under conditions effective to facilitate an additionreaction and to form a product stream comprising1,1,1,3-tetrachloropropane,

(b) dehydrochlorinating the 1,1,1,3-tetrachloropropane formed in step(a) in the absence or presence of a dehydrochlorination catalyst underconditions effective to form a product stream comprising3,3,3-trichloro-1-propene and/or 1,1,3-trichloro-1-propene,

(c) contacting carbon tetrachloride with the 3,3,3-trichloro-1-propeneand/or 1,1,3-trichloro-1-propene formed in step (b) in the presence ofan effective amount of a metal catalyst complex comprising a metal andan organic ligand under conditions effective to facilitate an additionreaction and to form a product stream comprising1,1,1,2,4,4,4-heptachlorobutane,

(d) contacting HF with the 1,1,1,2,4,4,4-heptachlorobutane obtained instep (c) in the presence or absence of a fluorination catalyst underconditions effective to facilitate a fluorination reaction and to form aproduct stream comprising cis- and trans-1,1,1,4,4,4-hexafluoro-2-buteneand/or 1,1,1,4,4,4-hexafluoro-2-chlorobutane,

(e) optionally dehydrochlorinating the1,1,1,4,4,4-hexafluoro-2-chlorobutane, in the presence or absence of adehydrochlorination catalyst under conditions effective to form aproduct stream comprising a mixture of cis- andtrans-1,1,1,4,4,4-hexafluoro-2-butene, and

(f) optionally, after isolating the cis-1,1,1,4,4,4-hexafluoro-2-buteneproduct from trans-1,1,1,4,4,4-hexafluoro-2-butene, contacting thetrans-1,1,1,4,4,4-hexafluoro-2-butene with an isomerization catalystunder conditions effective to form cis-1,1,1,4,4,4-hexafluoro-2-butene,preferably in substantial amounts.

Optionally but preferably, steps (a), (b) and (c) described above arecombined into one reaction, thereby providing another embodiment of thepresent invention, namely a process comprising the steps of:

(a) contacting carbon tetrachloride with ethylene in the presence of aneffective amount of a metal catalyst complex comprising a metal and anorganic ligand under conditions effective to facilitate an additionreaction and to form a product stream comprising1,1,1,2,4,4,4-heptachlorobutane, and

(b) contacting HF with the 1,1,1,2,4,4,4-heptachlorobutane formed instep (a) under conditions effective to facilitate a fluorinationreaction and to form a product stream mixture comprising1,1,1,4,4,4-hexafluoro-2-butene and/or1,1,1,4,4,4-hexafluoro-2-chlorobutane and isolating the1,1,1,4,4,4-hexafluoro-2-butene therefrom.

DETAILED DESCRIPTION OF THE INVENTION

Starting with carbon tetrachloride and ethylene,1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336) can be prepared through thefollowing reaction steps:

-   -   (a) CCl₄+CH₂═CH₂→CCl₃CH₂CH₂Cl (HCC-250)    -   (b) CCl₃CH₂CH₂Cl→HCl+CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl    -   (c) CCl₄+CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl→CCl₃CHClCH₂CCl₃    -   (d) Cl₃CHClCH₂CCl₃+HF→CF₃CH═CHCF₃ (HFO-1336)+CF₃CHClCH₂CF₃+HCl    -   (e) CF₃CHClCH₂CF₃→HCl+CF₃CH═CHCF₃ (HFO-1336)

The reactions of steps (a), (b), and (c) may be conducted in onereaction vessel. Two isomers, i.e., cis-CF₃CH═CHCF₃ andtrans-CF₃CH═CHCF₃, are generally produced during the reactions of steps(d) and (e). The cis-isomer is the desired product in some applications.In order to increase the single pass yield of the cis-isomer, thetrans-1336 can be isomerized into cis-1336 with the help of anisomerization catalyst, in another optional step (f):

-   -   (f) trans-1336→cis-1336

Detailed Process Descriptions Step (a): CCl₄+CH₂═CH₂→CCl₃CH₂CH₂Cl(HCC-250)

In this step, carbon tetrachloride is reacted with ethylene in thepresence of an effective amount of a metal catalyst complex comprising ametal and an organic ligand under conditions effective to facilitate anaddition reaction and to form a product stream comprising1,1,1,3-tetrachloropropane.

In preferred embodiment, the metal catalyst complex has a boiling pointhigher than that of 1,1,1,3-tetrachloropropane product, the metal is atransition metal selected from a group consisting of copper and iron,and the organic ligand is selected from the group consisting of primaryand secondary amines having a backbone of 4 or more carbon atoms,nitrites having a backbone of 3 or more carbon atoms, amides having abackbone of two or more carbon atoms, and phosphates or phosphiteshaving a backbone of 3 or more carbon atoms. Particularly, preferredcombinations of catalysts and organic ligands are provided in Table 1.Mixtures of the above combination (e.g., mixture of 17 and 18) can alsowork very well.

TABLE 1 Preferred Complexes Combination 1 Catalyst Organic Ligand 1Cuprous chloride t-alkylamine 2 Cuprous chloride t-butylamine 3 Cuprouschloride p-alkylamine 4 Cuprous chloride Stearylamine 5 Cuprous chlorideLaurylamine 6 Cuprous chloride Cyclohexylamine 7 Cuprous chlorideOctylamine 8 Cuprous chloride 2-ethylhexylamine 9 Cuprous chloride2-octylamine 10 Cuprous chloride Tert-octylamine 11 Cuprous chlorideDiaminododecane C₁₂H₂₈N₂ 12 Iron powder Tribuylphosphate 13 Iron powderHexamethylenephosphoramide 14 Iron powder Triphenylphosphate 15 Ferricchloride Tributylphosphate 16 Fe powder/Ferric Triethyl phosphatechloride 17 Fe powder/Ferric Trimethyl phosphate chloride 18 Ferrouschloride Tributylphosphate 19 Ferrous chloride Triphenylphosphate

The catalyst complex is used in an amount sufficient to catalyze thereaction of carbon tetrachloride and ethylene. Preferably, theconcentration of the catalyst in the reaction mixture ranges from about0.01 to about 10 wt. %, preferably from about 1 to about 5 wt. %, andmore preferably from about 1.5 to about 2.5 wt. %.

To achieve favorable selectivity and yields, it is preferable to achievegood mixing of at least a portion of the catalyst complex in thereactions. To this end, the catalyst may be added to the reactorcontaining carbon tetrachloride, ethylene and organic ligand, or carbontetrachloride and ethylene may be added to a reactor containing thecatalyst and organic ligand.

The reaction should be conducted under operating conditions sufficientto effect the addition reaction of carbon tetrachloride and ethylene ina continuous process. The reaction temperatures can be ranged from about40° C. to about 180° C., and preferably, from about 50° C. to about 110°C. Reaction pressure is typically maintained by removing a productstream containing the HCC-250 product from the reactor. Generally, thepressure should be maintained to achieve desired contact times. It hasbeen found that reaction pressures of about 1 psig to about 400 psig arepreferred, while pressures of about 50 to about 200 psig are even morepreferred. Contact times tend to vary according to the catalyst used andthe reaction conditions. Suitable results have been obtained withcontact times from about 10 seconds to about 10 hours, and preferablyfrom about 1 minute to about 5 hours. Preferably, the reactor effluentis fed to distillation column(s) for organic separation.

Step (b): CCl₃CH₂CH₂Cl→HCl+CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl

In this step, CCl₃CH₂CH₂Cl is fed to a vapor phase reactor(dehydrochlorination reactor) to be dehydrochlorinated with the help ofa dehydrochlorination catalyst to make the desired intermediateCCl₃CH═CH₂. The effluent stream exiting reactor may optionally compriseadditional components, such as un-reacted CCl₃CH₂CH₂Cl, HCl, andCCl₂═CHCH₂Cl.

The catalysts may be metal halides, halogenated metal oxides, neutral(or zero oxidation state) metal or metal alloy, or activated carbon inbulk or supported form. In metal halides or metal oxides catalysts,component metals include, but are not limited to, Cr³⁺, Fe³⁺, Mg²⁺,Ca²⁺, Ni²⁺, Zn²⁺, Pd²⁺, Li⁺, Na⁺, K⁺, and Cs⁺. Component halogensinclude, but are not limited to, F⁻, Cl⁻, Br⁻, and I⁻. Halogenationtreatments can include any of those known in the prior art, particularlythose that employ HF, F₂, HCl, Cl₂, HBr, Br₂, HI, and I₂ as thehalogenation source. In neutral, i.e., zero valent, metal and metalalloy catalysts, useful metals include, but are not limited to, Pd, Pt,Rh, Fe, Co, Ni, Cu, Mo, Cr, Mn, and combinations of the foregoing asalloys or mixtures. The catalyst may be supported or unsupported. Usefulexamples of metal alloys include, but are not limited to, SS 316, Monel400, Inconel 825, Inconel 600, and Inconel 625.

Dehydrochlorination may optionally be carried out in presence or absenceof an oxidizing agent. Useful examples of oxidizing agents include, butare not limited to, oxygen and carbon dioxide. Use of an oxidizing agentcan extend the life of the catalyst. The oxidizing agent can be pure ordiluted with an inert gas such as nitrogen before being introduced intoreactor. The level of oxidizing agent is generally from about 1% toabout 10% by volume and preferably from about 2% to 5% by volume basedon the volume of the organic feed.

The reaction temperatures can be ranged from about 150° C. to about 600°C., preferably from about 200° C. to about 500° C., and even morepreferably from about 250° C. to about 400° C. The reaction pressure ispreferably about 0 to 150 psig. Preferably, the reactor effluent is fedto a caustic scrubber or to a distillation column to remove theby-product of HCl to produce an acid-free organic product which,optionally, may undergo further purification.

Step (c): CCl₄+CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl→CCl₃CHClCH₂CCl₃

In this step, carbon tetrachloride is reacted with CCl₃CH═CH₂ and/orCCl₂═CHCH₂Cl in the presence of an effective amount of a metal catalystcomplex comprising a metal and an organic ligand under conditionseffective to facilitate an addition reaction and to form a productstream comprising CCl₃CHClCH₂CCl₃.

In preferred embodiments, the metal catalyst complex has a boiling pointhigher than that of CCl₃CHClCH₂CCl₃ product, the metal is a transitionmetal selected from a group consisting of copper and iron, and theorganic ligand is selected from the group consisting of primary andsecondary amines having a backbone of 4 or more carbon atoms, nitriteshaving a backbone of 3 or more carbon atoms, amides having a backbone oftwo or more carbon atoms, and phosphates or phosphites having a backboneof 3 or more carbon atoms. Particularly, preferred combinations ofcatalysts and organic ligands are provided in Table 2. Mixtures of theabove combination (e.g., mixture of 17 and 18) can also work very well.

TABLE 2 Preferred Complexes Combination 1 Catalyst Organic Ligand 1Cuprous chloride t-alkylamine 2 Cuprous chloride t-butylamine 3 Cuprouschloride p-alkylamine 4 Cuprous chloride Stearylamine 5 Cuprous chlorideLaurylamine 6 Cuprous chloride Cyclohexylamine 7 Cuprous chlorideOctylamine 8 Cuprous chloride 2-ethylhexylamine 9 Cuprous chloride2-octylamine 10 Cuprous chloride Tert-octylamine 11 Cuprous chlorideDiaminododecane C₁₂H₂₈N₂ 12 Iron powder Tribuylphosphate 13 Iron powderHexamethylenephosphoramide 14 Iron powder Triphenylphosphate 15 Ferricchloride Tributylphosphate 16 Fe powder/Ferric Triethyl phosphatechloride 17 Fe powder/Ferric Trimethyl phosphate chloride 18 Ferrouschloride Tributylphosphate 19 Ferrous chloride Triphenylphosphate

The catalyst complex is used in an amount sufficient to catalyze thereaction of carbon tetrachloride and CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl.Preferably, the concentration of the catalyst in the reaction mixtureranges from about 0.01 to about 10 wt. %, preferably from about 1 toabout 5 wt. %, and more preferably from about 1.5 to about 2.5 wt. %.

To achieve favorable selectivity and yields, it is preferable to achievegood mixing of at least a portion of the catalyst complex in thereactions. To this end, the catalyst may be added to the reactorcontaining carbon tetrachloride, CCl₃CH═CH₂ and/or CCl₂═CHCH₂Cl andorganic ligand, or carbon tetrachloride and CCl₃CH═CH₂ and/orCCl₂═CHCH₂Cl may be added to a reactor containing the catalyst andorganic ligand.

The reaction should be conducted under operating conditions sufficientto effect the addition reaction of carbon tetrachloride and CCl₃CH═CH₂and/or CCl₂═CHCH₂Cl in a continuous process. The reaction temperaturescan be ranged from about 40° C. to about 180° C., and preferably, fromabout 50° C. to about 110° C. Reaction pressure is typically maintainedby removing a product stream containing CCl₃CHClCH₂CCl₃ product from thereactor. Generally, the pressure should be maintained to achieve desiredcontact times. It has been found that reaction pressures of about 1 psigto about 400 psig are preferred, while pressures of about 50 psig toabout 200 psig are even more preferred. Contact times tend to varyaccording to the catalyst used and the reaction conditions. Suitableresults have been obtained with contact times from about 10 seconds toabout 10 hours, and preferably from about 1 minute to about 5 hours.Preferably, the reactor effluent is fed to distillation column(s) fororganic separation.

Optionally, but preferably, steps (a), (b) and (c) are combined in onereaction step (a)′, in which CCl₃CHClCH₂CCl₃ is directly synthesizedfrom carbon tetrachloride and ethylene.

Step (a)′: CCl₄+CH₂→CH₂→CCl₃CHClCH₂CCl₃

In this step, carbon tetrachloride is reacted with ethylene in thepresence of an effective amount of a metal catalyst complex comprising ametal and an organic ligand under conditions effective to facilitate anaddition reaction and to form a product stream comprisingCCl₃CHClCH₂CCl₃.

In a preferred embodiment, the metal catalyst complex has a boilingpoint higher than that of CCl₃CHClCH₂CCl₃ product, the metal is atransition metal selected from a group consisting of copper and iron,and the organic ligand is selected from the group consisting of primaryand secondary amines having a backbone of 4 or more carbon atoms,nitrites having a backbone of 3 or more carbon atoms, amides having abackbone of two or more carbon atoms, and phosphates or phosphiteshaving a backbone of 3 or more carbon atoms. Particularly, preferredcombinations of catalysts and organic ligands are provided in Table 3.Mixtures of the Table 2 complexes (e.g., a mixture of 17 and 18) canalso work very well.

TABLE 3 Preferred Complexes Combination 1 Catalyst Organic Ligand 1Cuprous chloride t-alkylamine 2 Cuprous chloride t-butylamine 3 Cuprouschloride p-alkylamine 4 Cuprous chloride Stearylamine 5 Cuprous chlorideLaurylamine 6 Cuprous chloride Cyclohexylamine 7 Cuprous chlorideOctylamine 8 Cuprous chloride 2-ethylhexylamine 9 Cuprous chloride2-octylamine 10 Cuprous chloride Tert-octylamine 11 Cuprous chlorideDiaminododecane C₁₂H₂₈N₂ 12 Iron powder Tribuylphosphate 13 Iron powderHexamethylenephosphoramide 14 Iron powder Triphenylphosphate 15 Ferricchloride Tributylphosphate 16 Fe powder/Ferric Triethyl phosphatechloride 17 Fe powder/Ferric Trimethyl phosphate chloride 18 Ferrouschloride Tributylphosphate 19 Ferrous chloride Triphenylphosphate

The catalyst complex is used in an amount sufficient to catalyze thereaction of carbon tetrachloride and ethylene. Preferably, theconcentration of the catalyst in the reaction mixture ranges from about0.01 to about 10 wt. %, preferably from about 1 to about 5 wt. %, andmore preferably from about 1.5 to about 2.5 wt. %.

To achieve favorable selectivity and yields, it is preferable to achievegood mixing of at least a portion of the catalyst complex in thereactions. To this end, the catalyst may be added to the reactorcontaining carbon tetrachloride, ethylene and organic ligand, or carbontetrachloride and ethylene may be added to a reactor containing thecatalyst and organic ligand.

The reaction should be conducted under operating conditions sufficientto effect the addition reaction of carbon tetrachloride and ethylene ina continuous process. The reaction temperatures can be ranged from about40° C. to about 180° C., and preferably, from about 50° C. to about 110°C. Reaction pressure is typically maintained by removing a productstream containing the CCl₃CHClCH₂CCl₃ product from the reactor.Generally, the pressure should be maintained to achieve desired contacttimes. It has been found that reaction pressures of about 1 psig toabout 400 psig are preferred, while pressures of about 50 to about 200psig are even more preferred. Contact times tend to vary according tothe catalyst used and the reaction conditions. Suitable results havebeen obtained with contact times from about 10 seconds to about 10hours, and preferably from about 1 minute to about 5 hours. Preferably,the reactor effluent is fed to distillation column(s) for organicseparation.

Step (d): CCl₃CHClCH₂CCl₃+HF→CF₃CH═CHCF₃(HFO-1336)+CF₃CHClCH₂CF₃+HCl

In this step, HF is reacted with 1,1,1,2,4,4,4-heptachlorobutane formedin step (d) in the presence of a fluorination catalyst under conditionseffective to facilitate a fluorination reaction and to form a productstream comprising 1,1,1,4,4,4-hexafluoro-2-butene and/or1,1,1,4,4,4-hexafluoro-2-chlorobutane. The effluent stream exitingreactor may optionally comprise additional components, such asun-reacted HF, and CF₃CHClCH₂CF₃. The fluorination process may becarried out in a vapor phase or a liquid phase.

In vapor-phase fluorination, HF (hydrogen fluoride gas) is fedcontinuously through the catalyst bed. After a short time with only theHF feed stream, CCl₃CHClCH₂CCl₃ is fed continuously through the catalystbed at a ratio of about 1:6 to about 1:30 and preferably from about 1:10to about 1:20 CCl₃CHClCH₂CCl₃/HF mole ratio. The reaction between HF andCCl₃CHClCH₂CCl₃ is carried out at a temperature from about 100° C. toabout 500° C., preferably from about 200° C. to about 350° C.; and at apressure of about 5 psig to about 200 psig (pounds per square inchgauge), preferably from about 20 psig to about 100 psig. Suitable vaporphase solid catalysts include, but are not limited to chromium,aluminum, cobalt, manganese, nickel and iron oxides, hydroxides,halides, oxyhalides, inorganic salts thereof and their mixtures.

Chromium (III) oxides such as crystalline chromium oxide or amorphouschromium oxide are preferred with amorphous chromium oxide being mostpreferred. Chromium oxide (Cr₂O₃) is a commercially available materialwhich may be purchased in a variety of particle sizes. The catalyst maybe supported on a substrate, such as on activated carbon, or may beunsupported or free-standing. In addition to activated carbon, usefulcatalyst supports include: alumina, fluorinated alumina, aluminumfluoride, alkaline earth metal oxides, fluorinated alkaline earth metaloxides, zinc oxide, zinc fluoride, tin oxide, and tin fluoride.Optionally but preferably, metal oxide catalysts are subject tofluorination treatment in HF flow at sufficiently high temperaturesprior to reaction.

In liquid phase fluorination, a liquid phase fluorination catalyst ischarged in a liquid form to a reactor and optionally activated with HF.Non-exhaustive list includes Lewis acids, transition metal halides,transition metal oxides, Group IVb metal halides, a Group Vb metalhalides, or combinations thereof. Non-exclusive examples of liquid phasefluorination catalysts are an antimony halide, a tin halide, a tantalumhalide, a titanium halide, a niobium halide, and molybdenum halide, aniron halide, a fluorinated chrome halide, a fluorinated chrome oxide orcombinations thereof.

Specific non-exclusive examples of liquid phase fluorination catalystsare SbCl₅, SbCl₃, SbF₅, SnCl₄, TaCl₅, TiCl₄, NbCl₅, MoCl₆, FeCl₃, afluorinated species of SbCl₅, a fluorinated species of SbCl₃, afluorinated species of SnCl₄, a fluorinated species of TaCl₅, afluorinated species of TiCl₄, a fluorinated species of NbCl₅, afluorinated species of MoCl₆, a fluorinated species of FeCl₃, orcombinations thereof. Antimony pentachloride is most preferred.

The activated catalyst is then heated to the desired reactiontemperature of about 30° C. to about 200° C., preferably from about 50°C. to about 120° C.; and the pressure is kept between about 15 psig toabout 200 psig, preferably from about 50 psig to about 175 psig. After ashort time with only HF feed, a CCl₃CHClCH₂CCl₃ feed stream is fedcontinuously through the catalyst at a ratio of about 1:6 to about 1:30and preferably about 1:10 to about 1:20 CCl₃CHClCH₂CCl₃/HF mole ratio.If necessary, the catalyst can be kept activated by the continuous orbatch addition of Cl₂ or a similar oxidizing agent.

The fluorination reaction is preferably carried out to achieve aconversion of about 70% or more, preferably about 90% or more, and mostpreferably about 93% or more. The selectivity for CF₃CH═CHCF₃ attainedis preferably about 60% or more and most preferably about 80% or more.

The fluorination is preferably carried out in a corrosion-resistantreaction vessel. Examples of corrosion-resistant materials areHastelloy, Nickel, Incoloy, Inconel, Monel and fluoropolymer linings.The vessel may have a fixed catalyst bed, or contain liquid catalyst. Ifdesired, inert gases such as nitrogen or argon may be employed in thereactor during operation. Preferably, the reactor effluent is fed to acaustic scrubber or to a distillation column or to an extractor toremove the by-product of HCl and un-converted HF to produce an acid-freeorganic product which, optionally, may undergo further purification.

Step (e): CF₃CHClCH₂CF₃→HCl+CF₃CH═CHCF₃(HFO-1336)

In this step, CF₃CHClCH₂CF₃, formed in step (d) as by-product, is fed toa vapor phase reactor (which contains a dehydrochlorination catalyst) tobe dehydrochlorinated to make the desired product HFO-1336.

The catalysts may be metal halides, halogenated metal oxides, neutral(or zero oxidation state) metal or metal alloy, or activated carbon inbulk or supported form. In metal halides or metal oxides catalysts,component metals include, but are not limited to, Cr³⁺, Fe³⁺, Mg²⁺,Ca²⁺, Ni²⁺, Pd²⁺, Li⁺, Na⁺, K⁺, and Cs⁺. Component halogens include, butare not limited to, F⁻, Br⁻, and I⁻. Halogenation treatments can includeany of those known in the prior art, particularly those that employ HF,F₂, HCl, Cl₂, HBr, Br₂, HI, and I₂ as the halogenation source.

In neutral, i.e., zero valent, metals and metal alloys catalysts, usefulmetals include, but are not limited to, Pd, Pt, Rh, Fe, Co, Ni, Cu, Mo,Cr, Mn, and combinations of the foregoing as alloys or mixtures. Thecatalyst may be supported or unsupported. Useful examples of metalalloys include, but are not limited to, SS 316, Monel 400, Inconel 825,Inconel 600, and Inconel 625.

Dehydrochlorination may optionally be carried out in presence or absenceof an oxidizing agent. Useful examples of oxidizing agents include, butare not limited to, oxygen and carbon dioxide. Use of an oxidizing agentcan extend the life of the catalyst. The oxidizing agent can be pure ordiluted with an inert gas such as nitrogen before being introduced intoreactor. The level of oxidizing agent is generally from about 1% toabout 10% by volume and preferably from about 2% to 5% by volume basedon the volume of the organic feed.

The reaction temperatures can be ranged from about 150° C. to about 600°C., preferably from about 200° C. to about 500° C., and even morepreferably from about 250° C. to about 400° C. The reaction pressure ispreferably from about 0 psig to 150 psig. Preferably, the reactoreffluent is fed to a caustic scrubber or to a distillation column toremove the by-product of HCl to produce an acid-free organic productwhich, optionally, may undergo further purification.

Step (f): trans-1336 cis-1336

Two isomers, i.e., cis-CF₃CH═CHCF₃ and trans-CF₃CH═CHCF₃, are generallyproduced during reactions of steps (d) and (e). When the cis-isomer isthe desired product, to increase the single pass yield of thecis-isomer, the trans-1336 is optionally but preferably isomerized intocis-1336 in a vapor phase reactor containing an isomerization catalyst.If the trans-isomer is preferred, similar isomerization reaction can beused to enrich the product stream with more trans-1336.

Three kinds of catalysts, namely, halogenated metal oxides, Lewis acidmetal halides, and zero-valent metals, can be used as isomerizationcatalysts. For catalysts which are halogenated metal oxide catalysts(which are sometimes referred to herein for convenience as HMOcatalysts) and Lewis Acid catalysts (which are sometimes referred toherein for convenience as LA catalysts), it is generally preferred thatthe catalysts include a transition metal or Al, and preferably when atransition metal is present it is selected from the group consisting oftransition metals with an atomic number from about 21 to about 57, andcombinations of these.

From among the transition metals for use in HMO and LA catalysts, metalsfrom Group VIB are preferred in certain embodiments, with Cr beingespecially preferred from among this group. In general for HMO and LAcatalysts which include a transition metal component, the metal ispreferably selected from the group consisting of Cr, Mo, V, Nb, Fe, La,Ni, Zn and combinations of these. In general for HMO and LA catalystswhich include rare earth metal component, the metal is preferably Ce. Ingeneral for HMO and LA catalysts which include boron metal component,the metal is preferably selected from Al, Tl, and combinations of these.In general for HMO and LA catalysts which include an alkali earth metalcomponent, the metal is preferably Mg. In general for HMO and LAcatalysts which include alkali metal components, the metal is preferablyselected from Li, Na, K and combinations of these. With respect toneutral metals catalysts (which are sometimes referred to herein forconvenience as NM catalysts), it is generally preferred that thecatalysts include one or more transition metals selected from groups VIIand IB, with Co and Pd being preferred in certain embodiments.

In preferred embodiments, reaction temperatures may be ranged from about50° C. to about 600° C., preferably from about 100° C. to about 400° C.,and even more preferably from about 150° C. to about 300° C. It is alsocontemplated that a wide variety of pressures may be used in connectionwith the processes of the present invention. Nevertheless, in certainpreferred embodiments, the reaction is carried out under pressureconditions ranging from a vacuum of about 5 ton to about 200 psig. It isalso contemplated that a wide variety of contact times for the preferredreactions of the present invention may be used. Nevertheless, in certainpreferred embodiments, the residence time is preferably from about 0.5seconds to about 600 seconds.

One aspect of preferred embodiments of the present invention includesconverting the trans-1336 to the cis-form, preferably at a conversion ofat least about 1 percent, more preferably at least around 20%, and evenmore preferably at least about 50%, while at the same time preferablyachieving a selectivity to the cis-form of the compound that is at leastabout 80%, even more preferably at least about 95%, and in certainhighly preferred embodiments at least about 98%.

The following examples are given as specific illustrations of theinvention. It should be noted, however, that the invention is notlimited to the specific details set forth in the examples.

EXAMPLE 1 Production of CCl₃CH₂CH₂Cl (HCC-250) from Carbon Tetrachlorideand Ethylene

To a 0.5 inch by 40 inch plug flow reactor that is packed iron wires, amixture (50/50 mole %) of ethylene and carbon tetrachloride is fed atabout 1.5 g/min. A catalyst mixture of ferric chloride,tributylphosphate and carbon tetrachloride, which is prepared in acatalyst pre-mix tank (2 liter), is also fed to the reactorsimultaneously at about 2 g/min. The reactor is operated at 80° C. to100° C. and controlled at about 30 psig to 100 psig. The effluent of theplug flow reactor is fed to a distillation column, which is operatedunder vacuum, for example at 30 mmHg, and about 50° C. to 60° C. Theunreacted carbon tetrachloride with trace amounts of ethylene aredistilled off from this distillation column, condensed and fed to thecatalyst pre-mix tank. The bottom mixture from this distillation is fedto a second distillation that is operated under vacuum, at about 50 mmHgand 80° C. to 90° C. The crude HCC-250 product is collected from the topof the column. The bottom mixture that contains the catalyst mixture,ferric chloride, ferrous chloride and tributylphosphate is fed back tothe catalyst pre-mix tank and subsequently, recycled back to thereactor. The crude HCC-250 contains 1.4 grams of HCC-250. The yield isgreater than 90%.

EXAMPLE 2 Production of CCl₃CH═CH₂

A cylindrical ¾ inch ID Monel reactor immersed into a 3-zone electricalfurnace is used in the dehydrochlorination reaction of HCC-250. Processtemperatures are recorded using a 5-point thermocouple placed inside thereactor and through the catalyst bed. 20 cc of 5% FeCl₃/carbon catalystis charged into the reactor. HCC-250 is fed into the bottom of thevertically mounted reactor at a rate of 12 g/h and is vaporized beforereaching catalyst bed. The reaction is conducted at 350° C. and 1 atm.Effluent gases are passed through a gas sampling tube so that theprogress of the reaction is monitored periodically via GC analysis ofthe contents of the gas sampling tube. Analysis indicates the effluentgases contain about 92% CCl₃CH═CH₂, about 3% CCl₂═CHCH₂Cl and about 5%HCC-250.

EXAMPLE 3 Production of CCl₃CHClCH₂CCl₃

To a 1 liter glass-lined autoclave equipped with an agitator, a mixture(50/50 mole %) of CCl₃CH═CH₂ and carbon tetrachloride is fed at about1.5 g/min. A catalyst mixture of ferric chloride, tributyl phosphate andcarbon tetrachloride, which is prepared in a catalyst pre-mix tank (2liters), is also fed to the reactor simultaneously at about 2 g/min. Thereactor is operated at about 100° C. and controlled at less than 80psig. The product mixture is removed continuously by using a dip tube,which is inserted about ⅔ of the autoclave. The product mixture is fedto a distillation column, which is operated at atmospheric pressure andabout 80° C. The unreacted carbon tetrachloride with trace amounts ofCCl₃CH═CH₂ are distilled off from this distillation column and fed tothe catalyst pre-mix tank. The bottom mixture from this distillation isfed to a second distillation that is operated under vacuum, at about 50mmHg and 80° C. to 90° C. The crude CCl₃CHClCH₂CCl₃ product is collectedfrom the top of the column. The bottom mixture that contains thecatalyst mixture, ferric chloride and tributyl phosphate is fed back tothe catalyst pre-mix tank. The crude CCl₃CHClCH₂CCl₃ contains 1.35 gramsof CCl₃CHClCH₂CCl₃. The yield is greater than 90%.

EXAMPLE 4 Production of CCl₃CHClCH₂CCl₃ Directly from CarbonTetrachloride and Ethylene

To a 1 liter glass-lined autoclave equipped with an agitator, a mixture(50/50 mole %) of ethylene and carbon tetrachloride is fed at about 1.5g/min. A catalyst mixture of Fe powder, ferric chloride,tributylphosphate and carbon tetrachloride, which is prepared in acatalyst pre-mix tank (2 liters), is also fed to the reactorsimultaneously at about 2 g/min. The reactor is operated at about 100°C. and controlled at less than 80 psig. The product mixture is removedcontinuously by using a dip tube, which is inserted about ⅔ of theautoclave. The product mixture is fed to a distillation column, which isoperated at atmospheric pressure and about 80° C. The unreacted carbontetrachloride with trace amounts of ethylene are distilled off from thisdistillation column and fed to the catalyst pre-mix tank. The bottommixture from this distillation is fed to a second distillation that isoperated under vacuum, at about 50 mmHg and 80° C. to 90° C. The crudeCCl₃CHClCH₂CCl₃ product is collected from the top of the column. Thebottom mixture that contains the catalyst mixture, Fe powder, ferricchloride and tributyl phosphate is fed back to the catalyst pre-mixtank. The crude CCl₃CHClCH₂CCl₃ contains 1.35 grams of CCl₃CHClCH₂CCl₃.The yield is greater than 90%.

EXAMPLE 5 Production of CF₃CH═CHCF₃ (HFO-1336) and CF₃CHClCH₂CF₃

The vapor phase fluorination of CCl₃CHClCH₂CCl₃ is conducted in thepresence fluorinated Cr₂O₃ catalyst. A continuous vapor phasefluorination reaction system consisting of N₂, HF, and organic feedsystems, feed vaporizer, superheater, 4 inch ID (inside diameter) Monelreactor, acid scrubber, drier, and product collection system is used tostudy the reaction. The reactor is loaded with about 6.5 liters offluorinated Cr₂O₃ catalyst. The reactor is then heated to a reactiontemperature of about 240° C. with a N₂ purge flowing over the catalyst.The reactor is at about 3 psig of pressure. HF feed is then introducedto the reactor via the vaporizer and superheater as a co-feed with theN₂ for 15 minutes when the N₂ flow is stopped. The HF flow rate isadjusted to 1.4 lb/hr and then CCl₃CHClCH₂CCl₃ feed is started to thereactor via the vaporizer and superheater. The feed rate ofCCl₃CHClCH₂CCl₃ is kept steady at about 1.2 lb/hr and HF feed is keptsteady at 1.4 lb/hr for about an 18 to 1 mole ratio of HF toCCl₃CHClCH₂CCl₃. Once the reaction starts the catalyst bed temperaturerises to a range of 250° C. to 260° C. The concentrations ofCF₃CH═CHCF₃, CF₃CHClCH₂CF₃, and CCl₃CHClCH₂CCl₃ in the effluent of thereactor are 92.9, 4.9, and 1.1 GC Area %, respectively.

EXAMPLE 6 Production of CF₃CH═CHCF₃ (HFO-1336) from CF₃CHClCH₂CF₃

A cylindrical ¾ inch ID Monel reactor immersed into a 3-zone electricalfurnace is used in the dehydrochlorination reaction of CF₃CHClCH₂CF₃.Process temperatures are recorded using a 5-point thermocouple placedinside the reactor and through the catalyst bed. 20 cc of fluorinatedchromia catalyst is charged into the reactor. CF₃CHClCH₂CF₃ is fed intothe bottom of the vertically mounted reactor at a rate of 12 g/h and isvaporized before reaching catalyst bed. The reaction is conducted at350° C. and 1 atm. Effluent gases are passed through a gas sampling tubeso that the progress of the reaction is monitored periodically via GCanalysis of the contents of the gas sampling tube. Analysis indicatesthe effluent gases contain about 91% CF₃CH═CHCF₃, and about 8%CF₃CHClCH₂CF₃.

EXAMPLE 7 Production of CF₃CH═CHCF₃ (HFO-1336) from CCl₃CHClCH₂CCl₃

The liquid phase fluorination of CCl₃CHClCH₂CCl₃ is conducted in thepresence SbCl₅. About 6100 grams of SbCl₅ are contained in aTeflon®-lined liquid phase reactor (Teflon is a trademark of E.I. duPontde Nemours & Co) equipped with a 2-inch ID packed column and acondenser. The reactor is 2.75-inch ID×36-inch long. A large excess ofCl₂ is first added to the reactor to ensure that the catalyst is in apentavalent state. The reactor is heated to about 85° C. to 87° C. HFfeed is started first. When 1.3 lbs (pounds) of HF have been added theCCl₃CHClCH₂CCl₃ feed is started. The purity of the CCl₃CHClCH₂CCl₃ feedstock is about 99 GC area % (gas chromatograph). The experiment runscontinuously for 71 hours. During this run, chlorine is fed batchwiseabout every 4 hours throughout the run to keep the catalyst active. Thefeeds averaged 0.495 lbs/hr HF, and 0.411 lbs/hr CCl₃CHClCH₂CCl₃ for an18/1 ratio of HF/CCl₃CHClCH₂CCl₃, and 135 seconds residence time. Thereactor temperature range for the experiment is 78° C. to 91° C. and thepressure range is 85 psig to 115 psig (pounds per square inch gauge).The organic crude material collected from the run is run on a gaschromatograph. The concentrations of CF₃CH═CHCF₃, and CCl₃CHClCH₂CCl₃ inorganic phase are 97.9, and 1.0 GC Area %, respectively.

EXAMPLE 8 Production of Cis-CF₃CH═CHCF₃ from Trans-CF₃CH═CHCF₃

A cylindrical Monel reactor of ¾ inch ID immersed into a 3-zoneelectrical furnace is used in the isomerization reaction oftrans-CF₃CH═CHCF₃. Process temperatures are recorded using a 5-pointthermocouple placed inside the reactor and through the catalyst bed. 20cc of fluorinated chromia catalyst is charged into the reactor.Trans-CF₃CH═CHCF₃ is fed into the bottom of the vertically mountedreactor at a rate of 12 g/h and is vaporized before reaching catalystbed. The reaction is conducted at 250° C. and 1 atm. Effluent gases arepassed through a gas sampling tube so that the progress of the reactionis monitored periodically via GC analysis of the contents of the gassampling tube. Analysis indicates the effluent gases contain about 61%cis-CF₃CH═CHCF₃, and about 38% trans-CF₃CH═CHCF₃.

While the present invention has been particularly shown and describedwith reference to preferred embodiments, it will be readily appreciatedby those of ordinary skill in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe invention. It is intended that the claims be interpreted to coverthe disclosed embodiment, those alternatives which have been discussedabove and all equivalents thereto.

What is claimed is:
 1. A process for the manufacture of1,1,1,4,4,4-hexafluoro-2-butene comprising the steps of: (a) contactingcarbon tetrachloride with ethylene in the presence of an effectiveamount of a metal catalyst complex comprising a metal and an organicligand under conditions effective to facilitate an addition reaction andto form a product stream comprising 1,1,1,2,4,4,4-heptachlorobutane, and(b) contacting HF with the 1,1,1,2,4,4,4-heptachlorobutane formed instep (a) under conditions effective to facilitate a fluorinationreaction and to form a product stream mixture comprising1,1,1,4,4,4-hexafluoro-2-butene and/or1,1,1,4,4,4-hexafluoro-2-chlorobutane and isolating the1,1,1,4,4,4-hexafluoro-2-butene therefrom.
 2. The process of claim 1,wherein the metal catalyst complex in step (a) has a boiling pointhigher than that of 1,1,1,2,4,4,4-heptachlorobutane.
 3. A process forthe manufacture of 1,1,1,4,4,4-hexafluoro-2-butene comprising the stepsof: (a) contacting carbon tetrachloride with ethylene in the presence ofan effective amount of a metal catalyst complex comprising a metal andan organic ligand under conditions effective to facilitate an additionreaction and to form a first product stream comprising1,1,1,3-tetrachloropropane, (b) dehydrochlorinating the1,1,1,3-tetrachloropropane formed in step (a) under conditions effectiveto form a second product stream mixture comprising3,3,3-trichloro-1-propene and/or 1,1,3-trichloro-1-propene, (c)contacting carbon tetrachloride with the product stream mixture formedin step (b) in the presence of an effective amount of a metal catalystcomplex comprising a metal and an organic ligand under conditionseffective to facilitate an addition reaction and to form a third productstream comprising 1,1,1,2,4,4,4-heptachlorobutane, and (d) contacting HFwith the 1,1,1,2,4,4,4-heptachlorobutane formed in step (c) underconditions effective to facilitate a fluorination reaction and to form afourth product stream mixture comprising 1,1,1,4,4,4-hexafluoro-2-buteneand/or 1,1,1,4,4,4-hexafluoro-2-chlorobutane and isolating the1,1,1,4,4,4-hexafluoro-2-butene therefrom.
 4. The process of claim 3,wherein the metal catalyst complex in step (a) has a boiling pointhigher than that of 1,1,1,3-tetrachloropropane.
 5. The process of claim2 or 4, wherein the metal in the metal catalyst complex is a transitionmetal or a mixture of transition metals.
 6. The process of claim 5,wherein the transition metal is selected from the group consisting ofcopper, iron and mixtures thereof.
 7. The process of claim 5, whereinthe organic ligand in the metal catalyst complex is selected from thegroup consisting of primary and secondary amines having a backbone of 4or more carbon atoms, nitrites having a backbone of 3 or more carbonatoms, amides having a backbone of two or more carbon atoms, andphosphates or phosphites having a backbone of 3 or more carbon atoms. 8.The process of claim 3, wherein step (b) takes place in the absence of adehydrochlorination catalyst.
 9. The process of claim 3, wherein step(b) takes place in the presence of a dehydrochlorination catalyst. 10.The process of claim 9, wherein the dehydrochlorination catalyst isselected from the group consisting of metal halides, halogenated metaloxides, neutral metal and metal alloys, activated carbon in bulk andsupported form, and mixtures thereof.
 11. The process of claim 10,wherein the metals in the metal halide and metal oxide catalysts areselected from the group consisting of Cr³⁺, Fe³⁺, Mg²⁺, Ca²⁺, Ni²⁺,Zn²⁺, Pd²⁺, Li⁺, Na⁺, K⁺, Cs⁺, and mixtures thereof.
 12. The process ofclaim 9, wherein the metals in the neutral metal and metal alloycatalysts are selected from the group consisting of Pd, Pt, Rh, Fe, Co,Ni, Cu, Mo, Cr, Mn, alloys and mixtures thereof.
 13. The process ofclaim 3, wherein the metal catalyst complex in step (c) has a boilingpoint higher than that of 1,1,1,2,4,4,4-heptachlorobutane.
 14. Theprocess of claim 13, wherein the metal in the metal catalyst complex isa transition metal or a mixture of transition metals.
 15. The process ofclaim 14, wherein the transition metal is selected from the groupconsisting of copper, iron and mixtures thereof.
 16. The process ofclaim 13, wherein the organic ligand in the metal catalyst complex isselected from the group consisting of primary and secondary amineshaving a backbone of 4 or more carbon atoms, nitrites having a backboneof 3 or more carbon atoms, amides having a backbone of two or morecarbon atoms, and phosphates or phosphites having a backbone of 3 ormore carbon atoms.
 17. The process of claim 1 or 3, wherein thefluorination reaction takes place in the absence of a fluorinationcatalyst.
 18. The process of claim 1 or 3, wherein the fluorinationreaction takes place in the presence of a fluorination catalyst.
 19. Theprocess of claim 18, wherein the fluorination reaction takes place in avapor phase.
 20. The process of claim 19, wherein the vapor phase solidcatalyst is selected from the group consisting of chromium, aluminum,cobalt, manganese, nickel and iron oxides, hydroxides, halides,oxyhalides, inorganic salts thereof and mixtures thereof.
 21. Theprocess of claim 20, wherein the vapor phase solid catalyst is achromium (III) oxide.
 22. The process of claim 21, wherein the chromium(III) oxide is a crystalline chromium oxide.
 23. The process of claim21, wherein the chromium (III) oxide is an amorphous chromium oxide. 24.The process of claim 18, wherein the fluorination reaction takes placein a liquid phase.
 25. The process of claim 24, wherein the liquid phasefluorination catalyst is selected from the group consisting of SbCl₅,SbCl₃, SbF₅, SnCl₄, TaCl₅, TiCl₄, NbCl₅, MoCl₆, FeCl₃, a fluorinatedspecies of SbCl₅, a fluorinated species of SbCl₃, a fluorinated speciesof SnCl₄, a fluorinated species of TaCl₅, a fluorinated species ofTiCl₄, a fluorinated species of NbCl₅, a fluorinated species of MoCl₆, afluorinated species of FeCl₃, and mixtures thereof.
 26. The process ofclaim 25, wherein the liquid phase fluorination catalyst is antimonypentachloride.
 27. The process of claim 3, further comprising step (e),dehydrochlorinating the 1,1,1,4,4,4-hexafluoro-2-chlorobutane underconditions effective to form a product stream comprising1,1,1,4,4,4-hexafluoro-2-butene.
 28. The process of claim 27, whereinstep (e) takes place in the presence of a dehydrochlorination catalyst.29. The process of claim 28, wherein the dehydrochlorination catalyst isselected from the group consisting of metal halides, halogenated metaloxides, neutral metal and metal alloys, activated carbon in bulk andsupported form, and mixtures thereof.
 30. The process of claim 29,wherein the metals in the metal halide and metal oxide catalysts areselected from the group consisting of Cr³⁺, Fe³⁺, Mg²⁺, Ca²⁺, Ni²⁺,Zn²⁺, Pd²⁺, Li⁺, Na⁺, K⁺, Cs⁺, and mixtures thereof.
 31. The process ofclaim 29, wherein the metals in the neutral metal and metal alloycatalysts are selected from the group consisting of Pd, Pt, Rh, Fe, Co,Ni, Cu, Mo, Cr, Mn, alloys and mixtures thereof.
 32. The process ofclaim 27, wherein step (e) takes place in the presence of an oxidizingagent.
 33. The process of claim 32, wherein the oxidizing agent isselected from the group consisting of oxygen, carbon dioxide, andmixtures thereof.
 34. The process of claim 32, wherein the oxidizingagent is further diluted with an inert gas.
 35. The process of claim 27,wherein step (e) takes place in the absence of an oxidizing agent. 36.The process of claim 27, wherein step (e) takes place in the absence ofa dehydrochlorination catalyst.
 37. The process of claim 1 or 3, furthercomprising the step of contacting trans-1,1,1,4,4,4-hexafluoro-2-butenewith an isomerization catalyst under conditions effective to formcis-1,1,1,4,4,4-hexafluoro-2-butene.
 38. The process of claim 37,wherein the isomerization catalyst is selected from the group consistingof halogenated metal oxides, Lewis acid metal halides, zero-valentmetals, and mixtures thereof.
 39. The process of claim 38, wherein thehalogenated metal oxide catalyst or the Lewis Acid metal halide catalystfurther includes a boron metal component.
 40. The process of claim 39,wherein the catalyst metal is selected from the group consisting of Al,Tl, and mixtures thereof.
 41. The process of claim 38, wherein thehalogenated metal oxide catalysts and Lewis Acid catalysts include atransition metal or Al.
 42. The process of claim 41, wherein thetransition metal is selected from the group consisting of Cr, Mo, V, Nb,Fe, La, Ni, Zn and mixtures thereof.
 43. The process of claim 42,wherein the transition metal is Cr.
 44. The process of claim 38, whereinthe neutral metal catalyst is selected from the group consisting of thetransition metals in Groups VII and IB, and mixtures thereof.